I had the same thing happen. Took it into the LBS and they tightened the BB. Creak went away. about 2 months later it came back but this time with a vibration along with a creak. Took to LBS and they said the BB was bad and replaced under warranty. 3 months later a creak came back this time it was the stock pedal. After replacing pedals it has been creak free for 2 years!